Punching machine with automatic cycle control

ABSTRACT

A power-rotated cam stores the time required to advance a punch press from a home position to a punching position and causes the press to be stopped in the home position when the press is returned toward the home position after punching a hole.

United States Patent [191 Kindgren [451 Nov. 18, 1975 PUNCI-IING MACHINEWITH AUTOMATIC CYCLE CONTROL [75] Inventor: Lee Kindgren, Rockford, ill.

[73] Assignee: W. A Whitney Corporation,

Rockford, Ill.

22 Filed: Nov. 4, 1974 21 Appi. No: 520,362

[52] US. Cl. 83/368; 83/370; 83/527; 83/530; 83/560 [51] Int. Cl. B26D5/02; B26F H14 [56] References Cited UNITED STATES PATENTS 2,548,562l0/l95l Slathar 83/71 X if ='Z/ I 1 ".1- I IF 1 l2/l974 Cantelia 83/530l/l975 Valente 83/560 X Primary ExaminerJ. M. Meister AssistantEraminer-Fred A. Silverberg Attorney, Agent, or Firm-Wolfe, Hubbard,Leydig, Voit & Osann, Ltd.

[57] ABSTRACT A power-rotated cam stores the time required to advance apunch press from a home position to a punching position and causes thepress to be stopped in the home position when the press is returnedtoward the home position after punching a hole.

6 Claims, 2 Drawing Figures Sheet 1 0f 2 3,919,907

US; Patfint Nov. 18, 1975 PUNCHING MACHINE WITH AUTOMATIC CYCLE CONTROLBACKGROUND OF THE INVENTION This invention relates to an automatic cyclecontrol for a punching machine and particularly for a machine of thetype which is adapted to punch holes in an elongated member such as anI-beam having a horizontal web with upstanding and depending sideflanges. Typically, the machine includes upper and lower punch pressesmounted on a vertically movable carriage and respectively adapted topunch holes in the upper and lower flanges of the beam. By moving thecarriage vertically, the presses can be located so as to punch holes atdifferent elevations in the flanges.

In the usual punching operation, the presses are initially adjusted in avertical direction to a home position in which the presses are centeredwith respect to the web of the beam and in which upper and lower gagingprobes associated with the presses will clear the web when the latter isadvanced to the presses. The gaging probes then are adjusted toestablish the proper vertical location for the holes in the flanges.Upon initiation of the punching cycle, the carriage moves verticallyuntil one of the probes contacts the web and stops the carriage.Thereafter, the hole is punched and the carriage returns the presses tothe home position. If a hole is to be punched in the other flange, thecarriage is moved vertically in the opposite direction and then returnsthe presses to the home position after punching of the hole.

When the machine is changed over to run beams having flanges with adifferent height, it is often necessary to re-adjust the home positionof the presses so that the presses and the gaging probes will not engagethe web as the beam is advanced. Accordingly, the home position of thepresses is not necessarily the same from run to run but indeed maychange when the machine is set up to operate on beams of differentsizes.

SUMMARY OF THE INVENTION The general aim of the present invention is toprovide a punching machine of the above character with a new andextremely simple automatic cycle control which returns the punch pressesto their last-established home position at the completion of eachpunching cycle even though the home position may change from cycle tocycle. lmportantly, the automatic return to the home position iseffected without need of adjusting the control when the home position ischanged.

A more detailed object is to achieve the foregoing through the provisionof a control which stores the time interval required to advance thepresses from the home position to the punching position and thenautomatically stops the return of presses after the presses have beenreturned through substantially the same time interval. Because thecontrol operates as a function of the time required to move the pressesand not as a function of their position, the control may return thepresses to the home position regardless of the location of the homeposition.

The invention also resides in the simple, low cost and trouble-freeconstruction of the control and in the use of the same control foreffecting cycling of both presses of the machine.

These and other objects and advantages of the invention will become moreapparent from the following de- 2 tailed description when taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view ofan exemplary punching machine equipped with a new and improved automaticcycle control embodying the unique features of the present invention.This view shows the machine somewhat schematically and partially incross-section.

FIG. 2 is a diagram of an electrical circuit with which the automaticcycle control is associated.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in thedrawings for purposes of illustration, the invention is embodied inmachine tool apparatus and particularly in a punching machine 10 havingupper and lower punch presses 11 and 12. The latter are adapted to punchholes in the inboard upper and lower flanges 13 and 14, respectively, ofan elongated [shaped member or beam 15 having a horizontal web 16. Thebeam is supported for lengthwise advancement by a power-driven rollerconveyor 17 and is periodically stopped at the presses in a punchingstation where one or more holes are punched in either or both flangesbefore the next advance of the beam.

Each of the'presses 11 and 12 comprises a C-shaped frame 19 having apunch 20 and a die 21 adapted to be located on opposite sides of theflange 13, 14. A double-acting hydraulic actuator 22 is mounted on eachframe and includes a reciprocable ram 23 for moving the respective punchinto and out of telescoping relation with the alined die and thus effectpunching of the holes.

Both press frames 19 are supported rigidly on a common carriage 24 whichis guided for up and down reciprocation on the main frame 25 of themachine 10. By adjusting the carriage upwardly and downwardly, thepunches 20 may be positioned at various elevations relative to theflanges 13, 14 and thereby punch the holes at selected vertical points.Adjustment of the carriage is effected by a double-acting hydraulicactuator comprising a cylinder 26 which is anchored to the main frame 25and which slidably receives a reciprocable rod-27 connected to thecarriage 24.

To establish the vertical location of the holes, the machine 10 includesupper and lower gaging probes 29 and 30 which are adapted to engageopposite sides of the web 16 of the beam 15 and stop vertical movementof the carriage 24 when the latter is advanced to place one of thepresses 11 and 12 in its punching position. The probes are carried onthe press frames 19 and thus move vertically in unison with the pressesl1 and 12 whenever the latter are shifted. In addition, the verticalposition of the probes may be adjusted independently of the presses bymanually turning a handwheel 31 to shift the probes through equaldistances but in opposite directions on the press frames. In this way,the elevation of t the probes relative to the elevation of the punches20 may be changed so as to stop the advance of the carriage 24 when thepunches are at different selected vertical punching positions.

In first setting up the machine 10 for operation on a given beam 15, theoperator turns the handwheel 31 to establish the desired gage settingfor the probe 29 and- /or the probe 30. The operator then manuallyadjusts the carriage 24 in a vertical direction to a home or startingposition in which the presses and the probes are substantially centeredwith respect to the web 16 of the beam. In other words, the carriage isinitially adjusted to a position in which the presses and the probes arespaced equidistantly from opposite sides of the web so that the pressesand the probes will not engage and rub against the web when the beam isadvanced. Manual adjustment of the carriage 24 in a downward directionmay be effected by closing a push button switch PB-D (FIG. 2) toenergize a solenoid SOL-D. This causes shifting of a control valve (notshown) to admit pressure fluid into the upper end of the cylinder 26 andproduce downward movement of the carriage. Similarly, closure of a pushbutton switch PB-U energizes a solenoid SOL-U and effects reverseshifting of the control valve so as to admit pressure fluid into thelower end of the cylinder and cause upward shifting of the carriage. Theflow of pressure fluid into and out of the cylinder is regulated bypressure compensated flow control valves 35 (FIG. 1) which meter thepressure fluid in such a manner as to cause the upward velocity of thecarriage to be substantially equal to the downward velocity.

After the presses 11 and 12 have been located in the home position andthe beam 15 has been located in the proper linear position, the machinemay be placed through an automatic cycle to effect punching of a hole.Assuming that a hole is to be punched in the upper flange 13, such anautomatic cycle begins with downward advance of the carriage 24. toshift the upper press 11 downwardly from its home position toward itspunching position. As the press reaches its punching position, the upperprobe 29 engages the upper side of the web 16 and stops further downwardmovement of the carriage. Thereafter, the actuator 22 of the upper pressis cycled to first extend its ram 23 and effect punching of the hole andthen to retract the ram and pull the punch 20 out of the die 21. Thecarriage then is returned upwardly to bring the presses back to the homeposition whereupon the carriage stops until the initiation of the nextcycle. If that cycle involves the punching of a hole in the lower flange14, the carriage first advances upwardly to shift the lower press 12from its home position to its punching position, the upward advance ofthe carriage being stopped by engagement of the lower probe 30 with thelower side of the web 16. After the lower press has punched the hole,the carriage is returned downwardly to shift the presses back to thehome position.

The operator may punch several holes in the beam at different elevationsand linear locations and then bring a new beam to the machine 10. If thenew beam has flanges of a different height than the previous beam, theweb of the beam will be located at a different elevation. Thus, theoperator may find it necessary to adjust the carriage 24 manually withthe push button switches PB-D or PB-U in order to set the presses 11 and12 in a new centered or home position so that the presses and the probes29 and 30 will clear the web of the beam when the latter is advanced.Accordingly, the home position is not fixed but instead is changed whenthe machine is set up to run a beam of a different size.

According to the present invention, provision is made of a very simpleand low cost control 40 (FIG. 2) which, during automatic cycling of themachine 10, always causes the presses 11 and 12 to return to the homeposition even though the location of the home position might be changedfrom cycle to cycle. The control operates by storing the time intervalrequired to 4 advance the presses from the home position and then byautomatically stopping the return of the presses when the presses havebeen returned through a time interval equal to the interval required foradvancement. Since the velocity of the presses is the same during theiradvance and return, the timing control is effective to stop the presseswhen the presses have returned through the same distance that theyadvance. By regulating movement of the presses as a function of timerather than position, the control causes the presses to always return tothe last-established home position regardless of the particular locationof the home position.

More specifically, the control 40 includes a reversible power-drivencontrol element or switch actuator which herein is in the form of a cam41 (FIG. 2) having a projecting lobe 43. The cam 41 is adapted to bedriven by the armature A of a small d.c. motor M having a separatelyexcited field, there being suitable reduction gearing (not shown)between the armature and the cam so that the cam will be rotated throughless than one revolution during an operating cycle of the machine 10.When the presses 11 and 12 are in the home position, the cam isangularly located as shown in FIG. 2 such that the lobe 43 holds acam-operated switch CS in an open condition. As the presses are advancedtoward the punching position, the motor M is energized and rotates thecam in one direction and at a substantially constant velocity to allowclosure of the cam switch CS. When the presses are stopped in thepunching position by the probe 29 or the probe 30, the motor issimultaneously stopped with the lobe spaced angularly from its originalstarting position. After the hole has been punched, the presses arereturned toward the home position and, at the same time, the motor isenergized to drive the cam reversely and return the lobe toward itsstarting position. The time interval required to move the lobe back toits starting position is the same as that which previously elapsed uponinitial driving of the cam during the advance of the presses and thus,when the lobe opens the cam switch CS to stop return of the presses, thelatter are located in the same home position.

The function of the control 40 in a complete operating cycle of themachine 10 now will be described. Let it be assumed that the operatorhas properly set the gaging probes 29 and 30 through the use of thehandwheel 31 and has manually adjusted the presses 11 and 12 to theproper home position through use of the push button switches PB-D orPB-U. Let it further be assumed that the operator wishes to use theupper press 11 to punch a hole in the upper flange 13 of the beam 15. Toachieve this, the operator first pivots an upperlower press selectorlever 45 (FIG. 2) counterclockwise to the upper or U position so as tomove a switch wiper 46 into position to energize a relay U and effectclosure of relay contacts U-l through U4. The operator then momentarilydepresses a push button switch PB-S to energize a relay P and start thepunching cycle. Relaycontacts P-l close to maintain the relay P in anenergized state after the operator releases the start switch PB-S.

Energization of relay P also closes contacts P-2 to energize a relay PADand close contacts PAD-l through PAD-4, the contacts PAD-4 closingpreparatory. When contacts PAD-l close, the solenoid SOL-D is energizedand causes the presses 11 and 12 to begin advancing downwardly from thehome position to the punching position. At the same time, a voltage ofpositive polarity is applied to the armature A of the motor M throughthe closed contacts PAD-2 and PAD-3. The motor thus begins rotating thecam 41, in one direction (assume clockwise) from its starting positionso that the lobe 43 allows the cam switch CS to close and energize arelay CH whose contacts CH-l close. preparatory.

Downward advance of the presses l1 and 12 continues until the upperprobe 29 engages the upper side of the web 16. Such engagement causesthe probe to close a switch PS-U with such closure resulting'inenergization of a relay RE to open contacts RE-l and close contacts RE-2and RE-3, the closure of contacts RE-2 servingto seal in the relay RE.As contacts RE-l open,

relay P is de-energized to open contacts P-2 and deenergize relay PAD.Contacts PAD-1, PAD-2 and PAD-3 thus open to stop the downward advanceof the presses and to de-energize the motor M.

Closure of the relay contacts RE-3 results in energization of a solenoidSOL-REU to shift a control'valve (not shown) for the hydraulic actuator22 of the upper press 11 and to cause the ram 23 of such actuator toextend and effect punching of the hole in the upper flange 13. Uponreaching its extended position, the ram closes a limit switch RE-U toenergize a relay RR whose contacts RR-l close to seal in the relay.Contacts RR-2 open to de-energize the relay RE and open the contactsRE-3 to stop further extension of the ram 23. Contacts RR-3 close toenergize a solenoid SOL-RRU and effect reversal of the control valve forthe actuator 22 and thereby cause retraction of the ram of the upperpress 11.

As the ram 23 of the upper press 11 reaches its retracted position, thepressure in the hydraulic system of the actuator 22 builds up and causesmomentary closure of a pressure-actuated switch SP. As a result, a relayPS is energized and opens its contacts PS-l to de energize relay RR andcause opening of contacts RR-3 and de-energization of solenoid SOL-RRUto stop fur ther retraction of the ram. Energization of the relay PSalso results in the closing of contacts PS-2 and energization of a relayPRU through those contacts and the closed contacts CH-l. Contacts PRU-1close to seal in the relay PRU around the contacts PS-2. When thesolenoid SOL-RRU is de-energize'd, the pressure in the hydraulic systemof the upper actuator 22 drops off to cause opening of the pressureswitch SP and de-energization of the relay PS.

When the relay PRU is energized, its contacts PRU-2 close to energizethe solenoid SOL-U and effect upward return of the presses 11 and 12from the punching position toward the home position. At the same time,

6 the motor M is not energized and thus the cam 41 remains in-itsstarting position and keeps the cam switch CS in its open state so thatthe switch will be compatible with the adjusted home. position.Accordingly, no adjustments need be made to the automatic cycle control40 when the home position of the presses is adjusted. v

When the operator wishes to punch a hole in the lower flange 14 of thebeam 15, the operation of the machine 10 is virtually the same asdescribed above except that the presses 11 and 12 first advance upwardlyfrom the home position, are stopped in the punching position by thelower probe 30 and an associated limit switch PS-L, and then returndownwardly to the home position after punching the hole. The selectorlever 45 is placed in the L-position and the various relays which areoperable during the cycle of the lower press are energized in thesequence of L, P, PAU, CH, RE, RR, PS

and PRD. De-energization' of the relays occurs in the relay contactsPRU-3 and PRU4 close to apply a voltage of opposite polarity to thearmature A of the motor M and thus effect reverse or counterclockwiserotation of the control cam 41' toward its starting position. The camreaches its starting position at the same time the presses l1 and 12reach the home position and, as an incident thereto, the lobe 43 opensthe cam switch CS to de-energize the relay CH. As a result, contactsCH-l open to de-energize the relay PRU, open the contacts PRU-2 andde-energize the solenoid SOL-U. Upward return of the presses thus isstopped so as to complete one punching cycle.

If the next cycle involves a beam of different size such as to requireadjustment of the home position of the presses 1 l and 12, the operatoreffects such adjustment by closing the push button switch PB-D or PB-U.During adjustment of the home position in this manner,

sequence of P, PAU, RE, RR, PS, CH and PRD. The solenoids SOL-REL andSOL-RRL control extension and retraction, respectively, of the ram 23 ofthe actuator 22 of the lower press 12 while the switch RE-L senses whenthe lower ram has reached its extended position. 7

During the cycle of the lower press 12, the cam 41 first rotates in acounterclockwise direction in moving from itsstarting position and thenrotates reversely during its return. Thus, the same cam and cam switchCS serve to control the cycles of both the upper press 11 and the lowerpress 12.

Those of ordinary skill in the art will appreciate that the circuitshown in FIG. 2 has been simplified greatly to facilitate ease ofunderstanding and that the control circuit of a commercial machine willinclude various safety interclocks, anti-repeat interlocks, resets andthe like. Also, the circuitry can be easily supplemented and modified toenable the lower press 12 to cycle immediately upon completion of thecycle of the upper press 11 and without need of the operator re-settingthe start switch PB-S.

I claim as my invention:

1. Apparatus for punching holes in an elongated member, said apparatuscomprising a conveyor for ad vancing said member along a generallyhorizontal path to a punching station, a punch press supported formovement in said punching station, means for causing said press toadvance in one direction from a home position and for stopping saidpress when the latter reaches a preselected punching position relativeto said member, means for causing actuation of said press when thelatter is in said punching position thereby to effect punching of a holein said member, means for thereafter causing said press to return in theopposite direction from said punching position at substantially the samevelocity as undertaken by the press in advancing to said punchingposition, means for storing the time interval required for said press toadvance from said home position to said punching position, and means forcausing the return of said press toward said home position to stop whenthe press has been returned through the substantially same time intervalwhereby the press is stopped in said home position.

2. Apparatus as defined in claim 1 in which said storing means comprisea reversible power-driven actuator, said last-mentioned means comprisingmeans positioned to be operated by said actuator when the latter is in apredetermined starting position, said apparatus 7 further includingmeans for driving said actuator away from said starting position duringadvance of said press from said home position to said punching positionand for stopping said actuator when said press reaches said punchingposition, and means for causing said actuator to be driven reverselytoward said starting position during the return of said press towardsaid home position.

3. Apparatus as defined in claim 2 further including means operable tocause said press to advance and return without causing driving of saidactuator whereby the home position of said press may be changed withoutchanging the starting position of said actuator.

4. Apparatus as defined in claim 2 in which said actuator comprises arotatable cam.

5. Apparatus for punching holes in an elongated member, said apparatuscomprising a conveyor for advancing said member along a generallyhorizontal path to a punching station, a punch press located in saidpunching station and supported for vertical bodily movement relative tosaid member, means for causing said press to advance vertically in onedirection from a home position and for stopping said press when thelatter reaches a preselected punching position relative to said member,a rotary control element, a reversible rotary motor connected to rotatesaid control element, means for causing said motor to advance saidcontrol element in one direction from astarting position when said pressadvances from said home position and to 8 stop said element when saidpress stops in said punching position, a switching device associatedwith said control element and adapted to be switched from a first stateto a second state as said element leaves said starting position, meansfor causing actuation of said press when the latter is in said punchingposition thereby to effect punching of a hole in said member, means forthereafter causing said press to return reversely toward said homeposition and simultaneously causing said motor to return said controlelement toward said starting position, said press and said controlelement returning at substantially the same velocities as undertaken bythe press and the element, respectively, during their advance, saidcontrol element causing said switching device to switch from said secondstate to said first state when said element returns to said startingposition, and means responsive to said switching device and operable tostop the return of said press and said control element when saidswitching device switches to said first state.

6. Apparatus as defined in claim 5 further including means operable tocause said press to advance and return without causing driving of saidcontrol element whereby the home position of said press may be changedwithout changing the starting position of said control element.

1. Apparatus for punching holes in an elongated member, said apparatuscomprising a conveyor for advancing said member along a generallyhorizontal path to a punching station, a punch press supported formovement in said punching station, means for causing said press toadvance in one direction from a home position and for stopping saidpress when the latter reaches a preselected punching position relativeto said member, means for causing actuation of said press when thelatter is in said punching position thereby to effect punching of a holein said member, means for thereafter causing said press to return in theopposite direction from said punching position at substantially the samevelocity as undertaken by the press in advancing to said punchingposition, means for storing the time interval required for said press toadvance from said home position to said punching position, and means forcausing the return of said press toward said home position to stop whenthe press has been returned through the substantially same time intervalwhereby the press is stopped in said home position.
 2. Apparatus asdefined in claim 1 in which said storing means comprise a reversiblepower-driven actuator, said last-mentioned means comprising meanspositioned to be operated by said actuator when the latter is in apredetermined starting position, said apparatus further including meansfor driving said actuator away from said starting position duringadvance of said press from said home position to said punching positionand for stopping said actuator when said press reaches said punchingposition, and means for causing said actuator to be driven reverselytoward said starting position during the return of said press towardsaid home position.
 3. Apparatus as defined in claim 2 further includingmeans operable to cause said press to advance and return without causingdriving of said actuator whereby the home position of said press may bechanged without changing the starting position of said actuator. 4.Apparatus as defined in claim 2 in which said actuator comprises arotatable cam.
 5. Apparatus for punching holes in an elongated member,said apparatus comprising a conveyor for advancing said member along agenerally horizontal path to a punching station, a punch press locatedin said punching station and supported for vertical bodily movementrelative to said member, means for causing said press to advancevertically in one direction from a home position and for stopping saidpress when the latter reaches a preselected punching position relativeto said member, a rotary control element, a reversible rotary motorconnected to rotate said control element, means for causing said motorto advance said control element in one direction from a startingposition when said press advances from said home position and to stopsaid element when said press stops in said punching position, aswitching device associated with said control element and adapted to beswitched from a first state to a second state as said element leavessaid starting position, means for causing actuation of said press whenthe latter is in said punching position thereby to effect punching of ahole in said member, means for thereafter causing said press to returnreversely toward said home position and simultaneously causing saidmotor to return said control element toward said starting position, saidpress and said control element returning at substantially the samevelocities as undertaken by the press and the element, respectively,during their advance, said control element causing said switching deviceto switch from said secOnd state to said first state when said elementreturns to said starting position, and means responsive to saidswitching device and operable to stop the return of said press and saidcontrol element when said switching device switches to said first state.6. Apparatus as defined in claim 5 further including means operable tocause said press to advance and return without causing driving of saidcontrol element whereby the home position of said press may be changedwithout changing the starting position of said control element.